Hydrogen evolution via glycerol photoreforming over Cu-Pt nanoalloys on TiO₂

Hydrogen production by the photoreforming of a glycerol solution using a 0.08 mol% bimetallic Cu-Pt/TiO₂ photocatalyst was investigated. CuO_x-PtO₂ deposits were loaded onto TiO₂ particles by impregnation followed by heat-treatment in air. XPS and H₂-TPR studies indicated an increased electron density in the Pt component of the deposits, attributed to an interaction between the Cu and Pt, which left it in a more reducible state. H₂ generation by the Cu-Pt deposits was found to outperform deposits of the single metals at equivalent metal loadings (i.e. 0.08 mol%), as well as the sum of the single metals (0.04 mol% loading each). The CuO_x-PtO₂ was reduced to alloyed metallic Cu-Pt deposits, in preference to proton reduction, during the initial reaction period, after which H₂ production was accelerated. Theoretical calculations reinforced the experimental studies, predicting an increased electron density on the Pt in the bimetallic Cu-Pt deposits compared with single metal Pt deposits. The Cu-Pt deposits favoured charge carrier separation which further enhanced the photocatalytic H₂ production process.